Monitoring oxygen production on mass-selected iridium–tantalum oxide electrocatalysts

Development of low-cost and high-performance oxygen evolution reaction catalysts is key to implementing polymer electrolyte membrane water electrolysers for hydrogen production. Iridium-based oxides are the state-of-the-art acidic but still suffer from inadequate activity stability, iridium’s scarcity motivates discovery with lower iridium loadings. Here we report a mass-selected iridium–tantalum oxide catalyst prepared by magnetron-based cluster source considerably reduced noble-metal loadings beyond commercial IrO2 catalyst. A sensitive electrochemistry/mass-spectrometry instrument coupled isotope labelling was employed investigate production rate under dynamic operating conditions account occurrence side reactions quantify number surface active sites. Iridium–tantalum nanoparticles smaller than 2 nm exhibit mass 1.2 ± 0.5 kA gIr–1 turnover frequency 2.3 0.9 s−1 at 320 mV overpotential, which two four times higher those IrO2, respectively. Density functional theory calculations reveal that special coordinations lowered aqueous decomposition free energy might be responsible enhanced performance. Low-cost, would facilitate implementation authors low-iridium high intrinsic in acid carefully evaluate parasitic reactions.